Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could glad glad you could glad glad she could glad glad we could glad glad you could glad glad they could glad glad
V-ing form
I could be glad glading you could be glad glading she could be glad glading we could be glad glading you could be glad glading they could be glad glading
Perfect
I could have glad gladed you could have glad gladed she could have glad gladed we could have glad gladed you could have glad gladed they could have glad gladed
V-ing perfect
I could have been glad glading you could have been glad glading she could have been glad glading we could have been glad glading you could have been glad glading they could have been glad glading
Negation
Simple form
I could not glad glad you could not glad glad she could not glad glad we could not glad glad you could not glad glad they could not glad glad
V-ing form
I could not be glad glading you could not be glad glading she could not be glad glading we could not be glad glading you could not be glad glading they could not be glad glading
Perfect
I could not have glad gladed you could not have glad gladed she could not have glad gladed we could not have glad gladed you could not have glad gladed they could not have glad gladed
V-ing perfect
I could not have been glad glading you could not have been glad glading she could not have been glad glading we could not have been glad glading you could not have been glad glading they could not have been glad glading
Interrogative form
Simple form
could I glad glad? could you glad glad? could she glad glad? could we glad glad? could you glad glad? could they glad glad?
V-ing form
could I be glad glading? could you be glad glading? could she be glad glading? could we be glad glading? could you be glad glading? could they be glad glading?
Perfect
could I have glad gladed? could you have glad gladed? could she have glad gladed? could we have glad gladed? could you have glad gladed? could they have glad gladed?
V-ing perfect
could I have been glad glading? could you have been glad glading? could she have been glad glading? could we have been glad glading? could you have been glad glading? could they have been glad glading?
Interro-negative form
Simple form
could I not glad glad? could you not glad glad? could she not glad glad? could we not glad glad? could you not glad glad? could they not glad glad?
V-ing form
could I not be glad glading? could you not be glad glading? could she not be glad glading? could we not be glad glading? could you not be glad glading? could they not be glad glading?
Perfect
could I not have glad gladed? could you not have glad gladed? could she not have glad gladed? could we not have glad gladed? could you not have glad gladed? could they not have glad gladed?
V-ing perfect
could I not have been glad glading? could you not have been glad glading? could she not have been glad glading? could we not have been glad glading? could you not have been glad glading? could they not have been glad glading?